Display panel

ABSTRACT

A display panel may have a first region and a second region encircled by the first region. The display panel may include first substrate, second substrate, sealant, conductive layer, and display medium layer. The first substrate may have a first recess in the first region. The second substrate may be disposed opposite to the first substrate. The sealant may be disposed between the first and second substrates, and may be received by the first recess. The conductive layer may be disposed on the first substrate, cover the first recess in a conformal manner, and be interposed between the first substrate and the sealant. The display medium layer may be disposed between the first and second substrates and may be encircled by the sealant. A thickness of the sealant may be larger than a distance between the first substrate and the second substrate in the second region.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure generally relates to an electronic device, inparticular, to a display panel.

2. Description of Related Art

In a typical display panel, a display medium layer is sandwiched betweena first substrate and a second substrate. The two substrates are kepttogether via a sealant to form a display cell. A thickness of thedisplay medium layer may influence the optical properties of the displaypanel. The sealant might assist to maintain a certain distance betweenthe first substrate and the second substrate. Structural requirements ofother components of the display panel might have to be considered whendesigning display panels with thin display medium layers.

SUMMARY OF THE INVENTION

Accordingly, the present disclosure is directed to a display panelincluding a substrate having a recess, and a sealant received by therecess.

According to an embodiment, a display panel may have a first region anda second region encircled by the first region. The display panel mayinclude a first substrate, a second substrate, a sealant, a conductivelayer, and a display medium layer. The first substrate may have a firstrecess in the first region. The second substrate may be disposedopposite to the first substrate. The sealant may be disposed between thefirst substrate and the second substrate, and may be received by thefirst recess. The conductive layer may be disposed on the firstsubstrate, may cover the first recess in a conformal manner, and may beinterposed between the first substrate and the sealant. The displaymedium layer may be disposed between the first substrate and the secondsubstrate and may be encircled by the sealant. A thickness of thesealant may be larger than a distance between the first substrate andthe second substrate in the second region of the display panel.

According to an embodiment, a width of the first recess may be greaterthan a width of the sealant.

According to an embodiment, the display panel may further have a thirdregion. The first region may be positioned between the third region andthe second region, and the conductive layer disposed on the firstsubstrate may continuously extend from the second region, pass throughthe first region and reach the third region to cover the first recess ina conformal manner.

According to an embodiment, the first substrate may have a firstthickness at the first region, a second thickness at the second regionand a third thickness at the third region, and the first thickness maybe smaller than either the second thickness or the third thickness.

According to an embodiment, side surfaces of the first recess may betapered.

According to an embodiment, a display panel may further include a lightshielding layer disposed on an outer surface of the first substratefurther away from the display medium layer. A vertical projection of thefirst recess may fall on the light shielding layer.

According to an embodiment, a width of the light shielding layer may belarger than a maximum width of the first recess.

According to an embodiment, a depth of the first recess may be smallerthan a half of the thickness of the first substrate at the secondregion.

According to an embodiment, a thickness of the display medium layer maybe smaller than 2 μm.

According to an embodiment, the second substrate may include a baseplate and a passivation layer disposed over the base plate, a secondrecess may be formed in the passivation layer at the first region, andthe sealant may be received by the second recess.

According to an embodiment, the second substrate may further include anactive device layer covered by the passivation layer. The passivationlayer may be interposed between the sealant and a portion of the activedevice layer.

According to an embodiment, the base plate may be a silicon bulk and theactive device layer may include a plurality of complementarymetal-oxide-semiconductor devices formed in the silicon bulk.

According to an embodiment, the sealant may include a sealing materialand a plurality of fillers distributed in the sealing material.

According to an embodiment, the display panel may further include afirst alignment layer disposed between the display medium layer and thefirst substrate and a second alignment layer disposed between thedisplay medium layer and the second substrate.

According to an embodiment, one or both of the first alignment layer andthe second alignment layer may include an inorganic alignment layer andan organic alignment layer, the inorganic alignment layer may be spacedfrom the sealant by a gap, and the organic alignment layer may belocated in the gap to be in contact with the sealant.

According to an embodiment, a display panel may have a first region anda second region encircled by the first region. The display panel mayinclude a first substrate, a second substrate, a sealant, and a displaymedium layer. The second substrate may be disposed opposite to the firstsubstrate. The second substrate may include a silicon bulk and apassivation layer disposed on the silicon bulk. A recess may be formedin the passivation layer at the first region. The sealant may bedisposed between the first substrate and the second substrate, and bereceived by the recess. A display medium layer may be disposed betweenthe first substrate and the second substrate, and be encircled by thesealant. A thickness of the sealant may be larger than a distancebetween the first substrate and the second substrate in the secondregion of the display panel.

According to an embodiment, the second substrate may further include anactive device layer formed in the silicon bulk and covered by thepassivation layer, and the passivation layer may be interposed betweenthe sealant and a portion of the active device layer.

According to an embodiment, the passivation layer may include a firstinsulation layer and a second insulation layer stacked on the firstinsulation layer.

According to an embodiment, a depth of the recess may be insufficient topass throughout a thickness of the first insulation layer.

According to an embodiment, the display panel may further include afirst alignment layer disposed between the display medium layer and thefirst substrate and a second alignment layer disposed between thedisplay medium layer and the second substrate.

According to an embodiment, one or both of the first alignment layer andthe second alignment layer may include an inorganic alignment layer andan organic alignment layer, the inorganic alignment layer may be spacedfrom the sealant by a gap, and the organic alignment layer may belocated in the gap to be in contact with the sealant.

According to an embodiment, the display panel may further have a thirdregion. The first region may be positioned between the third region andthe second region, and the first alignment layer and the secondalignment layer may be absent in the third region.

According to an embodiment, a thickness of the display medium layer issmaller than 2 μm.

In view of the above, a display panel in accordance with someembodiments of the disclosure has a first region surrounding a secondregion, and includes one or both of a first substrate and a secondsubstrate having a recess in the first region. A sealant is disposedbetween the first substrate and the second substrate and is received inthe recess. A distance between the first substrate and the secondsubstrate in the second region may be smaller than a thickness of thesealant. Accordingly, sealing with low compressibility may be used evenin the display panels requiring a small thickness of the display mediumlayer.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide further understandingof the disclosure, and are incorporated in and constitute a part of thisspecification. The drawings illustrate embodiments of the disclosureand, together with the description, serve to explain the principles ofthe disclosure.

FIG. 1 shows a schematic cross-sectional view of a display panelaccording to an embodiment of the present disclosure.

FIG. 2A to FIG. 2D show schematic cross-sectional views of a firstsubstrate undergoing a portion of the steps of a fabricating method inaccordance with an embodiment of the present disclosure.

FIG. 3A to FIG. 3D show schematic cross-sectional views of a displaypanel according to some embodiments of the present disclosure.

FIG. 4A shows a schematic cross-sectional view of a display panelaccording to an embodiment of the present disclosure.

FIG. 4B and FIG. 4C show schematic cross-sectional views of an enlargedportion of a display panel according to an embodiment of the presentdisclosure.

FIG. 5 shows a schematic cross-sectional view of a display panelaccording to some embodiments of the present disclosure.

In the drawings, the relative dimensions of the illustrated componentsmight have been altered for the sake of clarity.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the disclosure, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the descriptions to refer to the same or likeparts.

In the disclosure, the locution “an element A is disposed on an elementB”, used to describe a positional relationship, encompasses thepossibilities of one or multiple other elements disposed between theelement A and the element B, as well as the case of no other elementsexisting between the element A and the element B.

FIG. 1 shows a cross-sectional view of a display panel 100A according tosome embodiments of the present disclosure. As shown in thecross-sectional view of FIG. 1, the display panel 100A includes a firstsubstrate 110, a second substrate 120 opposite to the first substrate110, a display medium layer 130, and a sealant 140. The first substrate110 and the second substrate 120 are assembled via the sealant 140. Thedisplay medium layer 130 is sandwiched between the first substrate 110and the second substrate 120 and is surrounded by the sealant 140. Thedisplay medium layer 130 may be made of liquid crystals, so that thefirst substrate 110, the second substrate 120, the display medium layer130, and the sealant 140 may serve as a liquid crystal cell, but thedisclosure is not limited thereto. In some embodiments, a firstalignment layer 150 may be selectively disposed between the firstsubstrate 110 and the display medium layer 130, and a second alignmentlayer 160 may be selectively disposed between the display medium layer130 and the second substrate 120.

In some embodiments, the display panel 100A further includes ananti-reflective layer 114 and a light shielding layer 116 disposed on afirst surface 110 a of the first substrate 110. In some embodiments, thefirst substrate 110 may be made of glass, but the disclosure is notlimited thereto. In some embodiments, the first surface 110 a of thefirst substrate 110 is a surface farther away from the display mediumlayer 130. A material of the anti-reflective layer 114 may includesilicon oxide, titanium oxide, or a combination of both.

In some embodiments, the light shielding layer 116 has a frame-likepattern when viewed from top, but the disclosure is not limited thereto.In some alternative embodiments, the light shielding layer 116 may bedisposed following other patterns or layers, according to therequirements of the design. In some embodiments, both theanti-reflective layer 114 and the light shielding layer 116 may be inphysical contact with the first substrate 110 and bottom surfaces of theanti-reflective layer 114 and the light shielding layer 116 may becoplanar. In other words, the anti-reflective layer 114 may be absentfrom the regions where the light shielding layer 116 is disposed, butthe disclosure is not limited thereto. In some alternative embodiments,the anti-reflective layer 114 may extend over the whole first surface110 a of the first substrate 110, and be disposed between the lightshielding layer 116 and the first substrate 110. Namely, theanti-reflective layer 114 may be sandwiched between the light shieldinglayer 116 and the first substrate 110.

The light shielding layer 116 has a light shielding effect. The displaylight of the display panel 100A may be obstructed or shielded by thelight shielding layer 116 in a first region 102 of the display panel100A, so that a displayed image may be presented in a second region 104beside the first region 102. In other words, the second region 104 maybe a display area of the display panel 100A. In some embodiments, thefirst region 102 has a frame-like pattern when viewed from the top, andsurrounds the second region 104. A boundary between the first region 102and the second region 104 of the display panel 100A may be defined by aninner edge 116 i of the light shielding layer 116. Another boundary ofthe first region 102 may be defined by an outer edge 116 o opposite tothe inner edge 116 i of the light shielding layer 116. In someembodiments, the outer edge 116 o defines the boundary of the firstregion 102 and a third region 106 of the display panel 100A. The thirdregion 106 may be considered an outermost peripheral region of thedisplay panel 100A, and may be omitted in some embodiments. The lightshielding layer 116 may present a sharp pattern, with the inner edge 116i and the outer edge 116 o showing good linearity. A material for thelight shielding layer 116 may include organic inks, but the disclosureis not limited thereto.

In some embodiments, the first substrate 110 may present a first recessR1 in the first region 102 of the display panel 100A. The first recessR1 is formed in the first region 102 in a second surface 110 b of thefirst substrate 110 opposite to the first surface 110 a, so that thesecond surface 110 b of the first substrate 110 presents an unevenprofile. In some embodiments, a cross section of the first recess R1 mayhave a trapezoidal shape. That is, the first recess R1 may present aminimum width W_(min) at a bottom of the first recess R1 deep within thefirst substrate 110, and a maximum width W_(max) greater than theminimum width W_(min) where the first recess R1 starts recessing intothe first substrate 110. In other words, the side surfaces of the firstrecess R1 may be tapered. In some alternative embodiments, the sidesurfaces of the first recess R1 may not be tapered and thus the maximumwidth W_(max) and the minimum width W_(min) may be the same. The firstrecess R1 may have a frame-like pattern when viewed from top, similar tothe pattern of the light shielding layer 116. In some embodiments, thelight shielding layer 116 may be deposited following the pattern of thefirst recess R1, so that a vertical projection of the first recess R1falls on the light shielding layer 116. In some embodiments, the firstrecess R1 is entirely contained within the first region 102 of thedisplay panel 100A. That is, in some embodiments, the verticalprojection of the first recess R1 falls completely within a span of thelight shielding layer 116. In some embodiments, a width W₁₁₆ of thelight shielding layer 116 is not smaller than a maximum width W_(max) ofthe first recess R1.

In some embodiments, the first substrate 110 presents a first thicknessT₁₀₂ at the first region 102, a second thickness T₁₀₄ at the secondregion 104, and a third thickness T₁₀₆ at the third region 106. Becauseof the first recess R1, the first thickness T₁₀₂ may be smaller thaneither the second thickness T₁₀₄ or the third thickness T₁₀₆. In someembodiments, the first thickness T₁₀₂ is not less than a half of thesecond thickness T₁₀₄. In other words, a depth D_(R1) of the firstrecess R1 is smaller than a half of the second thickness T₁₀₄ of thefirst substrate 110 at the second region 104.

The display panel 100A further includes a conductive layer 118 disposedon a second surface 110 b of the first substrate 110. The second surface110 b may be the surface of the first substrate 110 closer to thedisplay medium layer 130. In some embodiments, the conductive layer 118may extend over the entire second surface 110 b of the first substrate110. In some embodiments, the conductive layer 118 is disposedconformally over the second surface 110 b of the first substrate 110.That is, a profile of the conductive layer 118 follows a profile of thesecond surface 110 b of the first substrate 110, so that the conductivelayer 118 conforms to the first recess R1. In other words, theconductive layer 118 is disposed on the first substrate 110, andcontinuously extends from the second region 104, passes through thefirst region 102 and reaches the third region 106 to cover the firstrecess R1 in a conformal manner. In the first region 102 of the displaypanel 100A, the conductive layer 118 is disposed between the firstsubstrate 110 and the sealant 140. In the second region 104 of thedisplay panel 100A, the conductive layer 118 is disposed between thefirst substrate 110 and the display medium layer 130. In someembodiments, a material of the conductive layer 118 includes ITO or anyother material that is conductive and transparent to the display light.

The second substrate 120 may be a transistor array substrate comprisinga base plate 122, such as a glass plate or a silicon backplane formed ofa silicon bulk, and an active device layer 124 disposed thereon. In someembodiments, the active device layer 124 and the conductive layer 118may be used for providing the driving electric field to drive thedisplay medium layer 130. In some embodiments, the second substrate 120may further optionally include a passivation layer 126 disposed over theactive device layer 124. The active device layer 124 may be a thin filmtransistor array, a CMOS (Complementary Metal-Oxide Semiconductor)device array, or the like. Accordingly, the display panel 100A may be aThin Film Transistor Liquid Crystal Display (TFT-LCD) panel or an LCoS(Liquid Crystal on Silicon) display panel.

In some embodiments, the display medium layer 130 may be disposedbetween the first substrate 110 and the second substrate 120 and fillthe space surrounded by the first substrate 110, the second substrate120 and the sealant 140. The display medium layer 130 may further extendfrom the second region 104 into the first region 102. That is, a smallportion of the display medium layer 130 may be covered by the lightshielding layer 116. A thickness T₁₃₀ of the display medium layer 130 isreferred to as a “cell gap”. Some optical properties of the displaymedium layer 130 such as the phase retardation may be influenced by thecell gap and the light transmittance of the display panel 100A isgenerally related to the phase retardation of the display medium layer130. For some applications, it might be preferable to use a thinnerdisplay medium layer. For example, a reflective liquid crystal displaypanel generally requires a smaller cell gap than a transmissive liquidcrystal display panel. Or, the display medium layer having higher valueof birefringence may require a smaller cell gap to achieve the desiredphase retardation. In some embodiment, a thickness T₁₃₀ of the displaymedium layer 130 may be smaller than 2 μm. To achieve a small cell gap,a distance D_(S) between the first substrate 110 and the secondsubstrate 120 in the second region 104 may be comparably small. In thepresent embodiment, the distance D_(S) is measured as the distancebetween the second surface 110 b of the first substrate 110 and asurface 126 a of the passivation layer 126 closer to the display mediumlayer 130. In some embodiments in which the passivation layer 126 is notincluded, the distance D_(S) is measured between the second surface 110b of the first substrate 110 and a surface 124 a of the active devicelayer 124 closer to the display medium layer 130.

The sealant 140 is disposed in the first region 102 of the display panel100A and is sandwiched between the first substrate 110 and the secondsubstrate 120. In some embodiments, the sealant 140 may contact theconductive layer 118 on the first substrate 110, and the passivationlayer 126 (if included) on the second substrate 120. In someembodiments, by leaning against the first substrate 110 at one end andthe second substrate 120 at the other end, the sealant 140 maycontribute to the stabilization of the distance D_(S) between the firstsubstrate 110 and the second substrate 120. In some embodiments, thesealant 140 encircles the display medium layer 130. In some embodiments,the sealant 140 has a frame-like structure surrounding the displaymedium layer 130 when viewed from top. In some embodiments, the sealant140 is received in the first recess R1 of the first substrate 110. Insome embodiments, the maximum width W_(max) and the minimum widthW_(min) of the first recess R1 are greater than a width W₁₄₀ of thesealant 140, but the disclosure is not limited thereto. In someembodiments, the width W₁₄₀ of the sealant 140 is comparable to theminimum width W_(min) of the first recess R1. That is, the sealant 140may fill the bottom of the first recess R1. In some alternativeembodiments, the first recess R1 may have a constant width and thesealant 140 may have the width W₁₄₀ not greater than the first recess R1so as to be received in the first recess R1. In some embodiments, thelight shielding layer 116 may be disposed in such a way to completelyshield the sealant 140.

In some embodiments, the sealant 140 may include a sealing material 142and a plurality of fillers 144 dispersed in the sealing material 142,but the disclosure is not limited thereto. In some embodiments, thesealant 140 may include only the sealing material 142 without thefillers 144. In some embodiments, the sealing material 142 may be athermally curable material, a photochemically curable material, or athermo-photocurable material. The sealing material 142 may includeorganic resins such as epoxy resin, polyurethane resins, furan-basedresins, acrylate resins, or the like. A material of the fillers 144 mayinclude glass fiber, plastics, siliconates, mica, or the like. Thefillers 144, by being dispersed into the sealing material 142, mayincrease the structural stability of the sealant 140, and, as such, ofthe entire display panel 100A. When designing a display panel accordingto some embodiments of the disclosure, the cell gap T₁₃₀ and thedistance D_(S) have to be taken into account when choosing the materialfor the sealant 140. For example, one of the factors to be considered ishow thin a material can be pressed. In some embodiments, byaccommodating the sealant 140 into the first recess R1, a thickness T₁₄₀of the sealant 140 may be greater than the distance D_(S) between thefirst substrate 110 and the second substrate 120 in the second region104, so that even less compressible materials can be used for thesealant 140. In some embodiments, the depth D_(R1) of the first recessR1 and a concentration and a size of the fillers 144 may be adjusted toreach the desired thickness T₁₃₀ for the display medium layer 130. Assuch, when designing a display panel according to some embodiments ofthe disclosure, a material of the sealant 140 can be chosen from a widerrange of candidate materials and small cell gaps (the thickness T₁₃₀),if so desired, are achievable without difficulty.

In some embodiments, the first alignment layer 150 and the secondalignment layer 160 may be disposed between the display medium layer 130and the first substrate 110 and between the display medium layer 130 andthe second substrate 120, respectively. The first and second alignmentlayers 150 and 160 may be disposed within the enclosure formed by thesealant 140, and may extend in the second region 104 of the displaypanel 110A and at least part of the first region 102. The first andsecond alignment layers 150 and 160 may be absent from the third region106 of the display panel 100A. The first and second alignment layers 150and 160 may be respective an organic alignment layer or an inorganicalignment layer. A material used for the organic alignment layer mayinclude polyimide, e.g. thermally curable polyimide or UV-curablepolyimide. A material of the inorganic alignment layer may includesilicon oxide (SiO_(x)), zinc oxide (ZnO) or nanoporous anodic aluminumoxide. In some embodiments, the first and second alignment layers 150and 160 may extend to partially overlap the sealant 140 and be incontact with the sealant 140. The first alignment layer 150 is disposedon the conductive layer 118, and interposed between the conductive layer118 and the display medium layer 130.

The fabrication process of the display panel 100A of FIG. 1 may includethe following steps, but is not limited thereto, and the order of thesteps is also not limited to the order presented here. Cross-sectionalviews of some manufacturing intermediates according to some embodimentsof the disclosure are shown in FIG. 2A-2E. As shown in FIG. 2A, asurface of the first substrate 110 is etched to be partially removed toform the first recess R1, where the etched surface is defined as thesurface (110 b) facing the display medium layer 140 in the finisheddisplay panel 100A as depicted in FIG. 1. The etching step may involve awet etching step (for example with hydrofluoric acid) or a dry etchingstep (for example with plasma). In some embodiments, either anisotropicor isotropic etching conditions may be used. Specifically, a patternedphotoresist PR may be used to shield from the etching agent portions ofthe first substrate 110 that are not be removed according to theintended design and may be removed from the first substrate 110 afterthe first recess R1 with the desired size and shape is formed.

Subsequently, as shown in FIG. 2B, on the first surface 110 a oppositeto the surface 110 b presenting the first recess R1, the anti-reflectivelayer 114 and the light shielding layer 116 may be formed (notnecessarily in the recited order) and the conductive layer 118 is formedon the second surface 110 b presenting the first recess R1 in aconformal manner. In some embodiments, the anti-reflective layer 114 isformed by the thermal deposition, and, if required, a pattern may begenerated through auxiliary masks (not shown) either during thedeposition step or during a subsequent etching step, but the disclosureis not limited thereto. In some embodiments, the light shielding layer116 is formed by inkjet printing or super-inkjet printing.

In FIG. 2C, the first alignment layer 150 is formed on top of theconductive layer 118. As shown in FIG. 2D, the sealing material 142 a isdispensed in the first recess R1 of the first substrate 110. In someembodiments, the sealing material 142 a is premixed with the fillers144. In some embodiments, the sealing material 142 a may be provided bydispensing, printing, or APR printing technology, but the disclosure isnot limited thereto. The sealing material 142 a though is not yet cured,has a certain viscosity to maintain the thickness without significantlyspreading and extending outwardly. A display medium material 130 a isdispensed on the first alignment layer 150 in the region surrounded bythe sealing material 142 a.

Subsequently, the first substrate 110 is assembled with the secondsubstrate 120 (shown in FIG. 1) having the second alignment layer 160(shown in FIG. 1) formed thereon. The second alignment layer 160 mayhave been formed on the second substrate 120 before the assembling stepwith the first substrate 110. During the assembling step, the sealingmaterial 142 a may be compressed. After assembling the second substrate120 with the first substrate 110, a curing step may be performed to curethe compressed sealing material 142 a. In some embodiments, the sealingmaterial 142 a may be a UV-curable sealant. In other words, anirradiation with a curing light having wavelength below about 400 nm (UVlight) may be required. The curing light may have maximum intensityaround 365 nm, depending on the material used for the sealing material142 a. Alternatively, the sealing material 142 a may be mainly curedwith UV light of wavelength of 365 nm. In some other embodiments, thesealing material 142 a may be cured by heat, and a baking step may beperformed. The temperature and the duration of the baking step may beselected according to the material used. Upon curing, formation of thedisplay panel 100A shown in FIG. 1 may be complete.

As shown in FIG. 1, in some embodiments, after the assembly of the firstsubstrate 110 with the second substrate 120 and the curing step, thethickness T₁₄₀ of the sealant 140 may be greater than the thickness T₁₃₀of the display medium layer 130. Furthermore, the thickness T₁₄₀ of thesealant 140 may be greater than the distance D_(S) between the firstsubstrate 110 and the second substrate 120 in the second region 104.

In FIG. 3A is shown a cross-sectional view of a display panel 100Baccording to another embodiment of the present disclosure. The structureof the display panel 100B shown in FIG. 3A may be an implementingexample of an embodiment of the present disclosure. The display panel100B shown in FIG. 3A is similar to the display panel 100A shown in FIG.1, and the same or similar reference numbers in the two embodimentsrepresent the same or similar elements or components. The display panel100B may include the first substrate 110, the anti-reflective layer 114,the light shielding layer 116, the conductive layer 118, the secondsubstrate 120, the display medium layer 130, the sealant 140, the firstalignment layer 150A, and the second alignment layer 160A. In theembodiment, the first alignment layer 150A includes a first organicalignment layer 152 and a first inorganic alignment layer 154, and thesecond alignment layer 160A includes a second organic alignment layer162 and a second inorganic alignment layer 164.

In some embodiments, the first inorganic alignment layer 154 is stackedon top of the first organic alignment layer 152. That is, the firstinorganic alignment layer 154 is disposed between the first organicalignment layer 152 and the display medium layer 130. In somealternative embodiments, the first organic alignment layer 152 and thefirst inorganic alignment layer 154 may be disposed on the firstsubstrate 110 in a coplanar manner. Accordingly, the first organicalignment layer 152 may not be interposed between the first inorganicalignment layer 154 and the first substrate 110.

In some embodiments, the second inorganic alignment layer 164 is stackedon top of the second organic alignment layer 162. That is, the secondinorganic alignment layer 164 is disposed between the second organicalignment layer 162 and the display medium layer 130. In somealternative embodiments, the second organic alignment layer 162 and thesecond inorganic alignment layer 164 may be disposed on the secondsubstrate 120 in a coplanar manner. Accordingly, the second organicalignment layer 162 may not be interposed between the second inorganicalignment layer 164 and the second substrate 120.

The organic alignment layers 152 and 162 may extend continuously fromthe second region 104 to a part of the first region 102 within an innerperimeter of the sealant 140, and physically contact the inner edge ofthe sealant 140. The first and second inorganic alignment layers 154 and164 may respectively be spaced apart from the sealant 140 by a gap G.That is, the first and second organic alignment layers 152 and 162 maybe disposed in the gap G, whilst the inorganic alignment layers 154 and164 may not extend within the gap G. The first and second organicalignment layers 152 and 162 and the first and second inorganicalignment layers 154 and 164 are in contact with the display mediumlayer 130. When the display medium layer 130 contains a liquid crystalmaterial, the two alignment layers 150A and 160A are used fororientating the liquid crystal molecules and inducing a pre-tilt anglein the liquid crystal molecules.

A material used for the first and second organic alignment layers 152and 162 may include polyimide. In some embodiments, the material of thefirst and second organic alignment layers 152 and 162 may includethermally curable polyimide or UV-curable polyimide. The first andsecond organic alignment layers 152 and 162 may have a thickness in arange of a couple of hundreds to a couple of thousands of angstroms. Amaterial of the first and second inorganic alignment layers 154 and 164may include silicon oxide (SiO_(x)), zinc oxide (ZnO) or nanoporousanodic aluminum oxide, but the disclosure is not limited thereto. Eachof the first and second inorganic alignment layers 154 and 164 may havea thickness in the range from 200 to 2000 angstroms.

In FIG. 3B is shown a cross-sectional view of a display panel 100Caccording to another embodiment of the present disclosure. The structureof the display panel 100C shown in FIG. 3B may be an implementingexample of an embodiment of the present disclosure. The display panel100C shown in FIG. 3B is similar to the display panel 100B shown in FIG.3A, and the same or similar reference numbers in the two embodimentsrepresent the same or similar elements or components. The display panel100C may include the first substrate 110, the anti-reflective layer 114,the light shielding layer 116, the conductive layer 118, the secondsubstrate 120, the display medium layer 130, the sealant 140A, the firstalignment layer 150B, and the second alignment layer 160B. The firstsubstrate 110 may present the first recess R1 in the first region 102 ofthe display panel 100C, where the sealant 140A is located. As for thedisplay panel 100B of FIG. 3, also in the display panel 100C, thesealant 140A is disposed in the first recess R1. A difference betweenthe display panel 100C shown in FIG. 3B and the display panel 100B shownin FIG. 3A is that the sealant 140A partly covers the first and secondorganic alignment layers 152A and 162A. That is, the first and secondorganic alignment layers 152A and 162A extend further into the recess R1or over the bottom substrate 120 than the first and second organicalignment layers 152 and 162 of the display panel 100B shown in FIG. 3A.Another difference between the display panel 100C of FIG. 3B and thedisplay panel 100B of FIG. 3A is that the first alignment layer 150B mayfurther include a first hydrophobic material layer 156 formed on thefirst inorganic alignment layer 154 and the second alignment layers 160Bmay further include a second hydrophobic material layer 166 formed onthe second inorganic alignment layer 164.

The first and second hydrophobic material layers 156 and 166 arerespectively disposed on the surfaces 154 a and 164 a of the first andsecond inorganic alignment layers 154 and 164. The surfaces 154 a and164 a are the surfaces of the first and second inorganic alignmentlayers 154 and 164 which interface with the display medium layer 130.The first and second hydrophobic material layers 156 and 166 may includehydrophobic molecules, such as silanes, fluorinated silanes, acids, orlong-chain alcohols. In some embodiments, if the material of the firstand second inorganic alignment layers 154 and 164 is obliquely depositedsilicon oxide, a resulting silane sidechain attached to silicon atoms atthe surfaces 154 a and 164 a may be Si—O—Si(ROH)₂—R′—CH₃ orSi—O—Si(ROH)₂—(CF₂)_(n)—CF₃, where R and R′ are alkyl chains which maybe different from each other and n, an integer number, represents thenumber of the carbon atoms of the alkyl chain. In some embodimentsincluding the aforementioned silane or a similar coating, the coatedsurfaces 154 a and 164 a of the first and second inorganic alignmentlayers 154 and 164 may have a water contact angle greater than 60degrees. Because of the attached hydrophobic molecules, the increasedhydrophobicity of the surfaces 154 a and 164 a may further facilitatepre-tilting and vertical alignment of the material of the display mediumlayer 130.

The fabrication process of the display panels 100B and 100C differ fromthe fabrication process of the display panel 100A in that, prior toassembly of the display panel, the first organic alignment layer 152 or152A and the first inorganic alignment layer 154 may be formed on top ofthe conductive layer 118. The method of forming the first organicalignment layer 152 or 152A (and the second organic alignment layer 162or 162A on the second substrate 120 shown in FIG. 3A) may includeink-jet printing or spin-coating and may further include patterning toform the desired pattern, but the method is not limited thereto. Themethod of forming the first inorganic alignment layer 154 (or the secondinorganic alignment layer 164 shown in FIG. 1) may include thermalevaporation of the desired material, but the method is not limitedthereto.

For the display panel 100C, the first and second hydrophobic materiallayers 156 and 166 are further respectively formed on the surfaces 154 aand 164 a of the first and second inorganic alignment layers 154 a and164 a. The disposing of the first and second hydrophobic material layers156 and 166 on the surfaces 154 a and 164 a of the first and secondinorganic alignment layers 154 and 164 may involve a surface treatmentor modification process, such as a silane surface treatment processthrough, for example, chemical vapor deposition. The surfaces 154 a and164 a may be treated in isolation by shielding other areas beyond thefirst and second inorganic alignment layers 154 and 164 with the use ofa mask (not shown) or by other selective deposition techniques. In someembodiments, a region corresponding to the gap G, or, in general, to theportions of the first and second organic alignment layers 152A and 162Aleft exposed by the first and second inorganic alignment layers 154 and164, may be shielded during the formation of the first and secondhydrophobic material layers 156 and 166, such that the first and secondorganic alignment layers 152A and 162A may not be subjected to thehydrophobic treatment.

In FIG. 3C is shown a cross-sectional view of a display panel 100Daccording to another embodiment of the present disclosure. The structureof the display panel 100D shown in FIG. 3C may be an implementingexample of an embodiment of the present disclosure. The display panel100D shown in FIG. 3C is similar to the display panel 100A shown in FIG.1, and the same or similar reference numbers in the two embodimentsrepresent the same or similar elements or components. The display panel100D having the first region 102 surrounding the second region 104served as the display region may include the first substrate 110, theanti-reflective layer 114, the light shielding layer 116, the conductivelayer 118, the second substrate 120, the display medium layer 130, thesealant 140, the first alignment layer 150, and the second alignmentlayer 160. The first substrate 110 may present the first recess R1 inthe first region 102 of the display panel 100D, where the sealant 140 islocated. As for the display panel 100A of FIG. 1, also in the displaypanel 100D the sealant 140 is disposed in the first recess R1. Thedisplay panel 100D of FIG. 3C differs from the display panel 100A ofFIG. 1 as a color filter 170 is disposed between the second alignmentlayer 160 and the second substrate 120 in the second region 104 of thedisplay panel 100D. In some embodiments, a peripheral portion of thecolor filter 170 may be disposed within the first region 102 of thedisplay panel 100D. In some alternative embodiments, a span of the colorfilter 170 may match or slightly exceed a span of the second alignmentlayer 160, but the disclosure is not limited thereto.

In FIG. 3D is shown a cross-sectional view of a display panel 100Eaccording to another embodiment of the present disclosure. The structureof the display panel 100E shown in FIG. 3D may be an implementingexample of an embodiment of the present disclosure. The display panel100E shown in FIG. 3D is similar to the display panel 100C shown in FIG.3B, and the same or similar reference numbers in the two embodimentsrepresent the same or similar elements or components. The display panel100E having the first region 102 surrounding the second region 104served as the display region may include the first substrate 110, theanti-reflective layer 114, the light shielding layer 116, the conductivelayer 118, the second substrate 120, the display medium layer 130, thesealant 140, the first alignment layer 150C, and the second alignmentlayer 160C. In the display panel 100E, the first and second organicalignment layers 152 and 162 extend up to the sealant 140, withoutoverlapping it, as discussed with reference to the display panel 100B ofFIG. 3A. The first and second hydrophobic material layers 156 and 166are formed on the first and second inorganic alignment layer 154 and164, respectively, similarly to what discussed with reference to thedisplay panel 100C of FIG. 3B. Furthermore, the display panel 100E ofFIG. 3D further includes the color filter 170 disposed between thesecond organic alignment layer 162 and the second substrate 120 in thesecond region 104, similarly to what discussed with reference to thedisplay panel 100D of FIG. 3C. In some embodiments, the span of thecolor filter 170 matches or slightly exceed the span of the secondhydrophobic material layer 166.

It is to be understood that, in some embodiments, all the display panelsof the present disclosure may include one or both of the first andsecond hydrophobic material layers 156 and 166. According to someembodiments, overlap between the sealant 140A and the first and secondorganic alignment layers 152A and 162A is possible for all the displaypanels of the present disclosure. Furthermore, in some embodiments, allthe display panels of the present disclosure may include the colorfilter 170.

In FIG. 4A is shown a cross section of a display panel 200 according toanother embodiment of the present disclosure. The structure of thedisplay panel 200 shown in FIG. 4A may be an implementing example of anembodiment of the present disclosure. The display panel 200 shown inFIG. 4A is similar to the display panel 100 shown in FIG. 1, and thesame or similar reference numbers in the two embodiments represent thesame or similar elements or components. The display panel 200 mayinclude the first substrate 210, the anti-reflective layer 114, thelight shielding layer 116, the conductive layer 218, the secondsubstrate 220, the display medium layer 130, the sealant 140, the firstalignment layer 150, and the second alignment layer 160. In someembodiments, the anti-reflective layer 114 and the light shielding layer116 are formed on the first surface 210 a of the first substrate 210further away from the display medium layer 130. A difference between thedisplay panel 200 of FIG. 4A and the display panel 100A of FIG. 1 isthat the first substrate 210 does not include a recess. In someembodiments, portions of the second surface 210 b of the first substrate210 closer to the display medium layer 130 in the first region 102, inthe second region 104, and in the third region 106 are substantiallycoplanar. In other words, no first recess is formed in the firstsubstrate 210. The conductive layer 218 is conformally disposed on thesecond surface 210 b of the first substrate 210. In other words, theconductive layer 218 may be a flat layer.

In some embodiments, the second substrate 220 includes the base plate222 having an active device layer 224 formed thereon, and a passivationlayer 226 disposed on the active device layer 224. In some embodiments,the base plate 222 includes a silicon bulk, and the active device layer224 includes a plurality of complementary metal-oxide semiconductordevices formed in the silicon bulk. In some embodiments, the activedevice layer 224 may include a thin film transistor array. In someembodiments, the active device layer 224 may be formed on a surface 222a of the base plate 222 closer to the display medium layer 130, andextends continuously within the first region 102 and the second region104. In some embodiments, the active device layer 224 further extendswithin the third region 106.

In the present embodiment, the passivation layer 226 covers the activedevice layer 224. The passivation layer 226 is interposed between thesealant 140 and the active device layer 224 in the first region 102, andbetween the active device layer 224 and the second alignment layer 160in the second region 104. In some embodiments, a material of thepassivation layer 226 includes organic insulating materials, such aspolymer-based insulating materials, or inorganic insulating materialssuch as oxides or nitrides. In some embodiments, the passivation layer226 may be formed by spin-on coating, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD), or the like, but thedisclosure is not limited thereto.

In addition, a second recess R2 is formed within the second substrate220, and the sealant 140 is received in the second recess R2. In someembodiments, as the sealant 140 is received in the second recess R2, thethickness T₁₄₀ of the sealant 140 may be larger than the distance D_(S)between the first substrate 210 and the second substrate 220 in thesecond region 104 of the display panel 200. In the present embodiment,the distance D_(S) is measured as the distance between the secondsurface 210 b of the first substrate 210 and a surface 226 a of thepassivation layer 226 closer to the display medium layer 130. In someembodiments, the thickness T₁₄₀ of the sealant 140 is greater than thethickness T₁₃₀ of the display medium layer 130. In some embodiments, thethickness T₁₃₀ of the display medium layer 130 may be smaller than 2 μm.The sealant 140 is received in the second recess R2 so that sealing withlow compressibility may be used even in the display panels requiring asmall thickness of the display medium layer 130.

In FIG. 4B is shown an enlarged view of a portion of a display panelaccording to some embodiments of the present disclosure. The enlargedportion shown in FIG. 4B corresponds to the portion inscribed in thearea A shown in FIG. 4A. FIG. 4B only illustrates the second substrate220 and the sealant 140 for descriptive purpose. In some embodiments thepassivation layer 226 may include a plurality of insulation layers. Asshown in FIG. 4B, in some embodiments the passivation layer 226 mayinclude a first insulation layer 2261 and a second insulation layer 2262stacked on the first insulation layer 2261. In some embodiments, thesecond recess R2 is formed by patterning the passivation layer 226. Insome embodiments, a portion of the second insulation layer 2262 isremoved by an etching step. In some embodiments, a corresponding portionof the first insulation layer 2261 may also be removed, but the etchingstep is carried out in such a way that a depth D_(R2) of the secondrecess R2 is insufficient to pass throughout a thickness T₂₂₆₁ of thefirst insulation layer 2261. In other words, at least a portion of thefirst insulation layer 2261 is interposed between the active devicelayer 224 and the sealant 140. In some alternative embodiments as shownin FIG. 4C, only a portion of the second insulation layer 2262 isremoved to form the second recess R2. In some embodiments, a material ofthe first insulation layer 2261 is different than a material of thesecond insulation layer 2262, so that selective etching conditions maybe applied to form the second recess R2 of the desired depth D_(R2).

According to some embodiments, the display panel in accordance with anyof the embodiments of the present disclosure may have a multi-layeredpassivation layer 226. Furthermore, the display panel 200 may furtherinclude a color filter (not shown in FIG. 4A), as discussed withreference to the display panel 100D of FIG. 3C. The display panel 200may further include hydrophobic material layers (not shown in FIG. 4A)formed on one or both of the alignment layers 150 and 160, as discussedwith reference to the display panel 100C shown in FIG. 3B. In addition,the display panel 200 may include both the color filter and thehydrophobic material layers, as discussed with reference to the displaypanel 100E of FIG. 3D.

In FIG. 5 is shown a cross section of a display panel 300 according toanother embodiment of the present disclosure. The structure of thedisplay panel 300 shown in FIG. 5 may be an implementing example of anembodiment of the present disclosure. The display panel 300 shown inFIG. 5 includes features similar to the display panel 100A shown in FIG.1, and features similar to the display panel 200 shown in FIG. 4A, andthe same or similar reference numbers in the three embodiments representthe same or similar elements or components. The display panel 300 ofFIG. 5 may include a first substrate 110 having a first recess R1 formedtherein as the display panel 100A of FIG. 1, and a second substrate 220having a second recess R2 formed therein as the display panel 200 ofFIG. 4A. The display panel 300 may further include the anti-reflectivelayer 114, the light shielding layer 116, the conductive layer 118, thedisplay medium layer 130, the sealant 140, the first alignment layer 150and the second alignment layer 160. The anti-reflective layer 114 andthe light shielding layer 116 may be disposed on the surface 110 a ofthe first substrate 110 further away from the display medium layer 130.The second substrate 220 may include the base plate 222, the activedevice layer 224 and the passivation layer 226. The conductive layer 118is conformally disposed over the second surface 110 b of the firstsubstrate 110, and follows the profile of the first recess R1 in thefirst region 102 of the display panel 300. The sealant 140 encircles thedisplay medium layer 130 and is received in the first recess R1 of thefirst substrate 110 and the second recess R2 of the second substrate220. In other words, a vertical projection of the first recess R1 fallsover a span of the second recess R2, so that the sealant 140 may besimultaneously disposed in both recesses R1 and R2. By having thesealant 140 disposed in the recesses R1 and R2 in the first region 102of the display panel 300, the thickness T₁₄₀ of the sealant 140 may begreater than the distance D_(S) between the first substrate 110 and thesecond substrate 220 in the second region 104 of the display panel 300.In some embodiments, the distance D_(S) is measured as the distancebetween the second surface 110 b of the first substrate 110 and thesurface 226 a of the passivation layer 226 closer to the display mediumlayer 130 in the second region 104 of the display panel 300. In someembodiments, the thickness T₁₄₀ of the sealant 140 is greater than thethickness T₁₃₀ of the display medium layer 130. In some embodiments, thethickness T₁₃₀ of the display medium layer 130 may be smaller than 2 μm.

In some embodiments, the conductive layer 118 is disposed between thesealant 140 and the first substrate 110. In some embodiments, at least aportion of the passivation layer 226 is disposed between the sealant 140and the active device layer 224 while the portion of the passivationlayer 226 may be thinner than the other portions of the passivationlayer 226. In some embodiments, the passivation layer 226 may have amulti-layered structure as previously discussed with reference to FIG.4B and FIG. 4C. Furthermore, the display panel 300 may further include acolor filter (not shown in FIG. 5), as discussed with reference to thedisplay panel 100D of FIG. 3C. The display panel 300 may further includehydrophobic material layers (not shown in FIG. 5) formed on one or bothof the alignment layers 150 and 160, as discussed with reference to thedisplay panel 100C shown in FIG. 3B. In addition, the display panel 300may include both the color filter and the hydrophobic material layers,as discussed with reference to the display panel 100E of FIG. 3D.

In light of the foregoing, a display panel according to an embodiment ofthe disclosure includes a sealant disposed between a first substrate anda second substrate in a first region of the display panel. One or bothof the first substrate and the second substrate may present a recess inthe first region where the sealant is received. By having the sealantdisposed within the recess of the first substrate or the secondsubstrate, a thickness of the sealant may be greater than a distancebetween the first substrate and the second substrate in a second regionof the display panel. The second region of the display panel may besurrounded by the first region, and may act as a display area for thedisplay panel. The possibility of having a thicker sealant in the firstregion expands the range of possible materials usable for the sealanteven when designing display panel having a particularly thin displaymedium layer (small gap) disposed between the first substrate and thesecond substrate in the second region of the display panel.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the present disclosurecovers modifications and variations of this disclosure, provided thesefalls within the scope of the following claims and their equivalents.

What is claimed is:
 1. A display panel having a first region and asecond region encircled by the first region, the display panelcomprising: a first substrate having a first recess in the first region;a second substrate opposite to the first substrate; a sealant disposedbetween the first substrate and the second substrate and received by thefirst recess; a conductive layer disposed on the first substrate,covering the first recess and interposed between the first substrate andthe sealant; a display medium layer disposed between the first substrateand the second substrate and encircled by the sealant, wherein athickness of the sealant is larger than a distance between the firstsubstrate and the second substrate in the second region of the displaypanel; a first alignment layer disposed between the display medium layerand the first substrate; and a second alignment layer disposed betweenthe display medium layer and the second substrate, wherein one or bothof the first alignment layer and the second alignment layer comprise aninorganic alignment layer and an organic alignment layer, the inorganicalignment layer is disposed between the display medium and the organicalignment and is spaced from the sealant by a gap, and the organicalignment layer is located in the gap and is in physical contact withthe sealant.
 2. The display panel of claim 1, wherein a width of thefirst recess is greater than a width of the sealant.
 3. The displaypanel of claim 1, wherein the display panel further has a third region,the first region is positioned between the third region and the secondregion, and the conductive layer disposed on the first substratecontinuously extends from the second region, passes through the firstregion and reaches the third region to cover the first recess in aconformal manner.
 4. The display panel of claim 3, wherein the firstsubstrate has a first thickness at the first region, a second thicknessat the second region and a third thickness at the third region, and thefirst thickness is smaller than either the second thickness or the thirdthickness.
 5. The display panel of claim 1, wherein side surfaces of thefirst recess are tapered.
 6. The display panel of claim 1, furthercomprising a light shielding layer disposed on an outer surface of thefirst substrate further away from the display medium layer, and avertical projection of the first recess falls on the light shieldinglayer.
 7. The display panel of claim 6, wherein a width of the lightshielding layer is larger than a maximum width of the first recess. 8.The display panel of claim 1, wherein a depth of the first recess issmaller than a half of the thickness of the first substrate at thesecond region.
 9. The display panel of claim 1, wherein a thickness ofthe display medium layer is smaller than 2 μm.
 10. The display panel ofclaim 1, wherein the second substrate comprises a base plate and apassivation layer disposed over the base plate, and a second recess isformed in the passivation layer at the first region, and the sealant isreceived by the second recess.
 11. The display panel of claim 10,wherein the second substrate further comprises an active device layercovered by the passivation layer, and the passivation layer isinterposed between the sealant and a portion of the active device layer.12. The display panel of claim 11, wherein the base plate is a siliconbulk and the active device layer comprises a plurality of complementarymetal-oxide-semiconductor devices formed in the silicon bulk.
 13. Thedisplay panel of claim 1, wherein the sealant comprises a sealingmaterial and a plurality of fillers distributed in the sealing material.14. A display panel having a first region and a second region encircledby the first region, the display panel comprising: a first substrate; asecond substrate opposite to the first substrate, wherein the secondsubstrate comprises a base plate comprising silicon and a passivationlayer disposed on the base plate, and a recess is formed in thepassivation layer at the first region; a sealant disposed between thefirst substrate and the second substrate and received by the recess; adisplay medium layer disposed between the first substrate and the secondsubstrate and encircled by the sealant, wherein a thickness of thesealant is larger than a distance between the first substrate and thesecond substrate in the second region of the display panel; a firstalignment layer disposed between the display medium layer and the firstsubstrate; and a second alignment layer disposed between the displaymedium layer and the second substrate, wherein one or both of the firstalignment layer and the second alignment layer comprise an inorganicalignment layer and an organic alignment layer, the inorganic alignmentlayer is disposed between the display medium and the organic alignmentand is spaced from the sealant by a gap, and the organic alignment layeris located in the gap and is in physical contact with the sealant. 15.The display panel of claim 14, wherein the second substrate furthercomprises an active device layer formed in the base plate and covered bythe passivation layer, and the passivation layer is interposed betweenthe sealant and a portion of the active device layer.
 16. The displaypanel of claim 14, wherein the passivation layer comprises a firstinsulation layer and a second insulation layer stacked on the firstinsulation layer.
 17. The display panel of claim 16, wherein a depth ofthe recess is insufficient to pass throughout a thickness of the firstinsulation layer.
 18. The display panel of claim 14, further having athird region, the first region being positioned between the third regionand the second region, wherein the first alignment layer and the secondalignment layer are absent in the third region.
 19. The display panel ofclaim 14, wherein a thickness of the display medium layer is smallerthan 2 μm.